TWiV 77: Non-nuclear proliferation

11 April 2010

Hosts: Vincent Racaniello, Alan Dove, and Rich Condit

Vincent, Alan, and Rich revisit circovirus contamination of Rotarix, then discuss poxvirus-like replication of mimivirus in the cell cytoplasm, and whether seasonal influenza immunization increases the risk of infection with the 2009 H1N1 pandemic virus.

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  • http://scienceblogs.com/effectmeassure revere

    Errrr…What exactly do you mean by a “blinded case-control study”? You can't do a RCT now and you couldn't well do it then. Or do you want to do a placebo-controlled RCT with the new trivalent vaccine? Since we know the trivalent vaccine with appropriate antigen matching works, that would be unethical. ]

  • gsgs

    RCT = randomized clinical trial
    some people in the Southern Hemisphere now blindly get either the old pandemrix
    or the new trivalent vax. Examine who gets sick

  • gsgs

    do it in a country where it's not unethical. Better a 50% chance on a working
    vaccine than no vaccine at all (as in most 3rd world countries)

  • http://www.virology.ws profvrr

    You are right, I didn't properly express my thoughts on what I meant
    by that comment. I had meant to highlight the fact that to determine
    the effect of seasonal vaccine on pandemic influenza, you would have
    to do a RCT with seasonal vaccine, then examine the incidence of
    pandemic influenza. I meant to comment on the difficulties of such a
    trial, including whether it is ethical or not, but never did. Ideally
    one would like to do a RCT with seasonal vaccine, pandemic vaccine,
    and placebo. We'll revisit next episode.

  • revere

    Vincent: no problem. These terms are used in a lot of different ways by non-epidemiologists (who are persnicketty and pedantic when it comes to language) and I wasn't sure what you meant.

    gsgs: Here's the problem. The ethics part isn't a question of law but a genuine question of what is right or wrong to do in medicine. If you know (as I think we do) that the seasonal vaccine is protective for seasonal virus, then withholding it in a placebo controlled trial is going to hurt those who get placebo. If you compare it to the pandemic vaccine, then we have the current problem: you might be harming the ones who get the seasonal vaccine for pH1N1 (or not helping them or not helping them maximally for a strain that is almost certainly circulating) although helping them for H3N2 and flu B. If you give them pandemic vaccine then you aren't protecting them from seasonal vaccine. We will still find out something about concurrent vaccinations from wave 2 in many places (including Canada), so we can find out something. Given the publicity, any RCT will likely have non-participation bias of one kind or another (possibly very hard to evaluate), so it doesn't remove any source of bias except the special (but important) one of residual confounding. Depending on other kinds of bias at work an RCT could even be less informative than a well designed observational study. So it's not a question, even on technical terms, of shopping around for a place that will let you do it (an ethically challenged procedure in itself and one no US academic who wanted to get federal grants for other work could afford to do).

  • gsgs

    so the USA is buying the ethics of their researchers with grants

  • natasa778

    Re the comment made in the podcast on regular human exposure to circovirus, the commentator (Alan or Rich) compared eating pork to receiving oral vaccine. These two things are not the same and cannot be compared, for the simple reason that most humans tend to COOK meat products before eating them.

    Therefore it would only be right to compare human circovirus exposure through oral vaccines to eating raw meat and drinking fresh pig blood. Not your usual infant diet.

  • welshandgrumpy

    There are fragments of the virus in the vaccine, cooking will likely leave at least fragments in the food – what's the difference…?

  • welshandgrumpy

    There are fragments of the virus in the vaccine, cooking will likely leave fragments in the food – what's the difference…?

  • Diane

    just wondering: i thought that the person who complained about Alan's jokes was making a joke himself “PUN-ished”?

  • http://www.virology.ws profvrr

    I do believe you are right about that!